ISO/TR 15608 Material Group 7.2: Martensitic stainless steels with C ≤ 0,35 % and 10,5 % ≤ Cr ≤ 30 %;
Martensitic stainless steels are similar to low alloy or carbon steels. In the annealed condition they have a structure similar to the ferritics, but when hardened they have a ‘body-centred tetragonal’, (bct), crystal lattice, rather than a body centred cubic, (bcc), lattice. Due to the deliberate addition of carbon, they can be hardened and strengthened by heat treatment, in a similar way to many carbon/carbon alloy steels. They are classed as a “hard” ferro-magnetic group. The main alloying element is chromium, with a typical content of 12-15%.
Martensitic grades have been developed with nitrogen and nickel additions, but with lower carbon levels than the traditional grades. These steels have improved toughness, weldability and corrosion resistance.
1.4313 and 1.4418. These low carbon martensitic grades have the benefit of being more weldable than other martensitic grades. Poor weldability is normally seen as a downside of martensitic steels due to their generally high carbon content, which requires pre and post heat treatment in welding. These steels are much better in this respect.
Typical materials in group 7.2
1Name/Grade | Number | Standard | Product | Remarks |
---|---|---|---|---|
F6a, Cl. 1 F6a, Cl. 2 F6a, Cl. 3 F6a, Cl. 4 410 TP410 410 F6 410 | S41000 S41000 S41000 S41000 S41000 S41000 S41000 S41000 S41000 | ASTM A-182 ASTM A-182 ASTM A-182 ASTM A-182 ASTM A-240 ASTM A-268 ASTM A-276 ASTM A-336 ASTM A-479 | Forging Forging Forging Forging Plate Smls. & welded tube Bar Forging Bar | ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC |
X2CrNi12 40 | 1.4003 S41003 | EN 10028-7 ASTM A-1010 | Plate Plate | – ASME BPVC |
410S | S41008 | ASTM A-240 | Plate | ASME BPVC |
F6b | S41026 | ASTM A-182 | Forging | ASME BPVC |
414 | S41400 | ASTM A-479 | Bar | ASME BPVC |
F6NM S41500 S41500 S41500 S41500 – | S41500 S41500 S41500 S41500 S41500 S41500 | ASTM A-182 ASTM A-240 ASTM A-268 ASTM A-479 ASTM A-731 ASTM A-815 | Forging Plate Smls. & welded tube Bar Smls. & welded pipe Fittings | ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC ASME BPVC |
F429 429 TP429 | S42900 S42900 S42900 | ASTM A-182 ASTM A-240 ASTM A-268 | Forging Plate Smls. & welded tube | ASME BPVC ASME BPVC ASME BPVC |
CA15 CA15 Cl. C | J91150 J91150 | ASTM A-217 ASTM A-487 | Casting Casting | ASME BPVC ASME BPVC |
CA15M Cl. A | J91151 | ASTM A-487 | Casting | ASME BPVC |
CA15 Cl. B CA15 Cl. D | J91171 J91171 | ASTM A-487 ASTM A-487 | Casting Casting | ASME BPVC ASME BPVC |
CA6NM CA6NM Cl. A CA6NM Cl. B | J91540 J91540 J91540 | ASTM A-352 ASTM A-487 ASTM A-487 | Casting Casting Casting | ASME BPVC ASME BPVC ASME BPVC |
X3CrNi13-4 | 1.4313 | EN 10222-5 | Forging | EN 13445-2 & EN 13480-2 |
X4CrNiMo16-5-1 | 1.4418 | EN 10272 | Bar | EN 13445-2 & EN 13480-2 |